In known methods, a CT image is calculated in each case from the measured data supplied from the individual rows. The data inconsistencies caused by the so-called cone angle (that is to say the inclination, of the rays to the image plane) occurring as a consequence of the use of a conical beam can be neglected in this case as long as the number of rows is sufficiently low and does not exceed 4, for example. In the case of detector systems with a larger number of rows, for example 16 rows, however, substantial artifacts occur in the CT images that are reconstructed on the basis of the measured data supplied from the outer rows.
Methods of the Feldkamp type, in which a 3D Back-projection is carried out after a convolution in the data, may be a solution to this problem. However, such methods are substantially more complex than 2D reconstruction methods.